import com.sun.security.jgss.GSSUtil;

import java.util.Stack;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 87111
 * Date: 2025-09-22
 * Time: 13:14
 */
public class Test {
    public static void main(String[] args) {
        StringBuffer s = new StringBuffer("abc");
        System.out.println(s);
        String s1 = "abcdr";
        System.out.println(s1);
        StringBuilder s2 = new StringBuilder();
        for(int i = 0; i < s1.length(); i++) {
            s2.append(s1.charAt(i));
        }
        System.out.println(s2);
        s2.append("gggg");
        System.out.println(s2);

        Stack<Integer> a = new Stack<>();
        a.push(1);
        a.push(2);
        a.push(3);
        a.push(4);

        System.out.println(a);


        StringBuffer s5 = new StringBuffer();
        System.out.println(s5);

    }
}
